Speaker construction



Dec. 26, 1961 c. A. SWANSON 1 3,014,996

SPEAKER CONSTRUCTION Filed May 18, 1956 2 Sheets-Sheet 1 INVENTOR. CARL A. 6WAN6OM by M, @11' TORMEYQ Dec. 26, 1961 c. A. swANsoN 3,014,996

SPEAKER CONSTRUCTION Filed May 18, 1956 2 Sheets-Sheet 2 INVENTOR. CARL. A. 6WAM5ON TTO RUE-V6 tire States 3,014,996 SEEAKER CONSTRUCTION Carl Axel Swanson, 3638 W. 89th St, Chicago, Ill. Fiied May 18, 1956, Ser. No. 585,693 3 Claims. (Ci. 179115.5)

This invention relates to a .speaker construction and more particularly, to the construction of a speaker of the type in which a voice coil is movable in an annular air gap of a magnetic structure and is connected to a cone or diaphragm. The voice coil is connected to an external circuit which may supply electrical power to cause vibration of the voice coil and generation of compression waves, or in the alternative, the external circuit may respond to an electrical signal generated in the voice coil by vibration of the diaphragm in response to sound waves.

In speaker constructions heretofore used, the ends of the voice coil wire extend radially outwardly from the voice coil and are cemented or otherwise secured to the diaphragm with flexible leads extending from the ends of the voice coil wires to terminals supported from the speaker frame. This manner of connection requires great care and skill and is a time-consuming operation. The flexible leads are particularly troublesome because they cause generation of spurious sounds which can be reduced to a satisfactory level only with great care and accuracy in the installation of the leads.

This invention was evolved with the object of providing a simple, easily effected method and arrangement of conmeeting the voice coil to an external circuit.

A further object of the invention is to provide a voice coil connection arrangement which is reliable in operation and in which the generation of spurious sounds is eliminated.

In brief, this invention provides a method and means for connection of the voice coil to an external circuit in which conductors extend along a voice coil centering disk in a manner by which the connections can be much more easily and reliably effected and by which the generation of spurious sounds is eliminated.

Other objects, features and advantages will become more fully apparent from the following detailed description taken in conjunction with the accompanying drawings which illustrate preferred embodiments, and in which:

FIGURE 1 is a side elevational view of a speaker constructed in accordance with the principles of this invention;

FIGURE 2 is an enlarged sectional view taken substantially along line II-II of FIGURE 1;

FIGURE 3 is a view taken substantially along line IIIIII of FIGURE 2;

FIGURE 4 is a view similar to FIGURE 3 but illustrating a modified arrangement;

FIGURE 5 is a sectional view taken substantially along line VV of FIGURE 4; and

FIGURE 6 is a plan view of a voice coil and centering disk sub-assembly using a modified connection arrangement.

As shown on the drawings:

Reference numeral 10 generally designates a speaker constructed according to the principles of this invention. The speaker 10 comprises a frame 11 having an annular rim portion 12 from which the peripheral edge of a cone or diaphragm 13 is flexibly supported. The frame 11 has an apertured generally conical portion 14 which converges from the rim 12 to a circular plate portion 15 on which a magnetic structure 16 is supported.

The magnetic structure 16 comprises a generally rectangular frame of magnetic material including a wal portion 17 secured against the plate portion 15 of the frame 11, a wall portion 18 in spaced parallel relation to the 3,014,996 Patented Dec. 26, 1961 portion 17, and wall portions 19 and 20 connecting the adjacent ends of the portions 17 and 18. A cylindrical permanent magnet 21 has one pole in engagement with the portion 18 with its other pole engaging a generally cylindrical pole piece 22, preferably of soft iron or the like, which extends into a circular opening 23 in the portion 17 to define an annular air gap 24. A dust cap or ring 25 of non-magnetic material such as brass, is supported by the pole piece 22 to engage the outer surface of the portion 17 about the opening 23.

A voice coil assembly 26 is secured in a centralopening of the cone or diaphragm 13 and extends into the air gap 24. The illustrated voice coil assembly comprises a voice coil 27 which is wound on a bobbin or cylinder 28 of paper or other insulating material. In the alternative, the wire could be of square cross-section or of a ribbon shape which might be wound either on a tubular form or might be cemented in a manner to be selfsupporting.

The voice coil 26 is also secured in a central opening of a centering disk 29 having a peripheral edge portion 30 secured to the surface of the circular plate portion 15 of the frame 11. The centering disk 29 is of somewhat flexible material and may have annular corrugations 31 to increase the flexibility thereof with respect to axial movement of the voice coil 28 while maintaining sufficient rigidity with respect to radial displacement of the voice coil.

According to this invention, strips 32 and 33 of conductive material project along the centering disk 29 from the voice coil 26 to spaced points at the peripheral edge of the centering disk 29. The strips 32 and 33 are respectively connected to end portions 34 and 35'of the voice coil wire 27. The outer end of the strip 32 engages a portion 36 of a terminal 37 having a portion 38 projecting through anopening in the plate portion 15 of the frame 11, to be connected to an external circuit. The outer end of the strip 33 directly engages the plate portion 15 of the frame 11 so as to be electrica'ly connected thereto, the frame being connectable to the external circuit. It will be appreciated, of course, that the strip 33 could be connected to a terminal similar to the terminal 37 insulated from the frame, if desired.

The strips 32 and 33 are formed by applying a conductive paint to the centering disk 29 which is of a porous material such as a fabric material. With this arrangement, the strips are effectively integral with the centering disk 29 so that they will flex therewith, to prevent the generation of spurious sounds.

In assembling the speaker, the voice coil 26 may be first cemented in the central opening of the centering disk 29. The end portions 34 and 35 of the voice coil wire 27 are then freed of insulating material and are bent down on the outside of the cylinder 28 to extend to a point adjacent the outer surface of the centering disk 29. The conductive paint may then be applied to form the strips 32 and 33 and to connect the inner ends of the strips 32 and 33 to the end portions 34 and 35 of the voice coil wire 27 in a single operation. Since the centering disk is of porous material, the conductive paint will extend to the other surface of the disk, to be .engageable with the portion 36 of the terminal 37 or with the frame portion 15.

Prior to installation of the voice coil and centering disk, a strip 39 of insulating material is mounted on the frame portion 13 and the terminal 37 is mounted thereon to thus be insulated from the frame. The centering disk and voice coil are then positioned to engage the outer end of the strip 32 with the portion 36 of the terminal 37. Cement may then be used to secure the peripheral edge of the disk 29 to the frame portion 15. The voice coil 26 may be cemented in the center opening of the cone or diaphragm 13 either before or after installation of the centering disk 29.

FEGURES 4 and 5 illustrate a modified arrangement in which the terminal ends and 41 of the wire of the voice coil 42 are brought out on one side of the voice coil and bent down to the surface of a centering disk 43 cemented to the voice coil 42. A pair of conductive strips 44 and 45 are electrically connected at their inner ends to the voice coil wire end portions 40 and 41 and extend radially outwardly to the peripheral edge of the centering disk 43. The outer ends of the strips 44 and 45 engage legs 46 and 47 of L-shaped members 48 and 49 having legs 50 and '51 extending through openings in a frame plate 52, the legs 50 and 51 forming terminals for connection to an external circuit. The legs 46 and 47 may be secured by rivets 53 and 54 to a strip 55 of insulating material which may be secured to the frame plate portion 52 by a pair of rivets 56.

With this arrangement, a terminal sub-assembly may be formed by securing the members 48 and 49 to the strip 55, and the sub-assembly may then be secured on the frame plate portion 52. The centering disk 43 together with the voice coil 42 are assembled and installed to engage the outer ends of the strips 44 and 45 with the legs 46 and 47, and the peripheral edge portion of the disk 43 may be then cemented to the frame plate portion 52.

FIGURE 6 is a plan view of the sub-assembly of a voice coil 57 and a centering disk'5-8. In this arrange ment, the disk 58 is of a woven material and very thin wires are woven into the material to form strips 59 and 60 which extend generally radially. The ends 61 and 62 of the wire of the voice coil 57 are freed of insulating material and bent down to points adjacent the inner ends of the strips 59 and 69, after which they are electrically connected thereto by applying solder 63 and 64. The wires which form the strips 59 and 60 are preferably woven into the fabric prior to formation of the fabric into the centering disk configuration. In this case, there will be another pair of strips 65 and 66 in line with the strips 59 and 60, but such are not electrically connected to anything and have no effect on operation. In the formation of the centering disk 58, a binding substance is preferably applied to integrally join the threads of the fabric at the crossing points, to prevent relative movement of the threads and generation of spurious sounds. The wires forming the strips 59, 60, 65 and 66, are, of course, integrally bonded to the fabric of the disk in the same operation.

It will be understood that modifications and variations may be effected without departing from the spirit and scope of the novel concepts of this invention.

1 claim as my invention:

1. In a transducer including a magnetic structure having an annular air gap, a voice coil assembly movable in said air gap, and a centering disc of a fabric material supporting said voice coil assembly for movement in said air gap, a strip of conductive material integrally embedded in said fabric material of said centering disc to extend radially from said voice coil assembly to the peripheral edge of said centering disc, a contact insulatingly supported on said magnetic structure, and cement means securing the periphery of said centering disc in fixed relation to said magnetic structure and arranged to hold the outer end portion of said strip of conductive material in firm engagement with said contact.

2. A transducer as defined'in claim 1, wherein said strip of conductive material is formed by conductive paint applied to said disc.

3. A transducer as defined by claim 1 wherein said strip of conductive material is formed by wires woven into said fabric material of said disc.

References Cited in the tile of this patent UNITED STATES PATENTS 1,907,687 Van Lis May 9, 1933 1,941,476 Jensen Jan. 2, 1934 2,046,515 Jensen July 7, 1936 2,221,068 Alons Nov. 12, 1946 2,524,836 Russell Oct. 10, 1950 2,538,621 Hopkins Jan. 17, 1951 2,554,859 Hoekstra et al. May 29, 1951 2,666,980 Russell Jan. 26, 1954 FOREIGN PATENTS 638,080 Great Britain May 31, 1950 686,934 Great Britain Feb. 4, 1953 

